excreting vs emission

excreting and emission both are nouns.

Word	Noun	Adjective	Verb	Adverb
excreting	Yes	No	No	No
emission	Yes	No	No	No

As nouns, emission is a hypernym of excreting; that is, emission is a word with a broader meaning than excreting:

excreting: the bodily process of discharging waste matter
emission: any of several bodily processes by which substances go out of the body

Other hypernyms of excreting include discharge, expelling.

excreting (noun)	emission (noun)
the bodily process of discharging waste matter	the act of emitting; causing to flow forth
	the occurrence of a flow of water (as from a pipe)
	the release of electrons from parent atoms
	any of several bodily processes by which substances go out of the body
	a substance that is emitted or released